Safety and arming mechanism for guided missiles



Dec. 4, 19621 5 F; JONES 3,066,605

SAFETY AND, RMING MECHNISM" FOR GUIDED MISSILES Filed May' 121 1961. 2 Sheets-Sheet l ,9 INVENTOR.

.Earl E'- Jones Dec. 4, 1962 E. F. JONES 3,066,605

SAFETY AND ARMING MECHANISM FOR GUIDED MISSILES INVENTOR. Earl E Innes ,Zyl Poma@ ma @wmf United States arent hhce 3,066,665 SAFETY AND ARMHNG MECHANISM FR GUIDED MISMLES Earl F. Jones, 318 Linda Vista, Las Cruces, N. Mex. Filed May 12, 1961, Ser. No. 109,790 1 Claim. (Cl. MP2-70.2) (Granted under Title 35, US. Code (1352), ses. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to a safety and arming mechanism for guided missiles and more particularly to a mechanism which provides safety and arming of guided missiles in ight by utilizing dynamic pressure caused by forward movement of the missile to rotate an impeller which in turn moves a detonator block into an armed position.

A guided missile arming mechanism, in order to be satisfactory, should require that three or four distinct and separate sequential occurrences be provided before arming takes place. The power source that drives the mechanism should be positive with no possible chance that the power lsource be disrupted. The primary requirement for a guided-missile armingl mechanism is that the missile become armed a predetermined safe distance above the launchers after take-off. Whether the arming mechanism is designed utilizing velocity or acceleration is immaterial. The present invention utilizies a detonator block which moves backward in a cage after missile takeoff, the time required for arming being a function of the stagnation pressure curve. The detonator charge is command fired electrically after the detonator block reaches the armed position.

The present invention also permits repeated testing of the mechanism while in the eld and without removing it from the missile.

It is a primary object of this invention to provide a simple safety and arming device for a missile consisting of only two moving parts.

Another object is to provide an arming device which eliminates escapement mechanisms, gear trains, safety pins and springs.

Another object is to provide an arming device for a missile that can be tested while the device is assembled in the missile.

A further object of the mechanism is to prevent the wind velocities found on the earths surface from causing operation of the mechanism to arm the missile.

A still further object is to provide an arming device that is sufficiently rugged t-o withstand rough handling of the missile without accidental arming.

A nal object of the invention is to provide an electrically red arming device having no electrical connections to the warhead of the missile.

The specific nature of the invention as Well as other objects and advantages thereof, will clearly appear from a description-of a preferred embodiment as shown in the'accompanying drawings in which:

FIG. 1 is a diagrammatic side View of a missile, showing the relative position of the arming mechanism with respect to the operating elements;

FIG. 2 is a perspective view, having a part of the casing cut away to expose the operating elements of the safety and arming mechanism;

FIG. 3 is a longitudinal section of the arming mechanism take along line 3-3 of FIG. 4;

FIG. 4 is a cross sectional view taken along line 4-4 of FIG. 3; and,

FIG. 5 is a diagrammatic view showing how a testing device can be used for testing the safety and arming mechanism without removing the same from the missile.

Referring to the drawings (FIG. l), reference character 1 indicates a missile generally and 2 a Pitot tube fixed to the nose of the missile.

The missile 1 is provided with a warhead 3 and a guidance system 4 for providing an electrical energy source. The arming mechanism is indicated generally by 6.

A Pitot tube line 7 connects the Pitot tube 2 with the mechanism 6 and a primacord 8 connects the arming mechanism 6 to warhead 3 while electrical leads 9 and 10 connect the guidance system 4 to mechanism 6 and complete the arming and firing elements of the missile'.

The arming mechanism 6 is illustrated in detail in FIGS. 2-4 and consists of a cylindrical casing indicated generally by 11 which houses the operating elements of the mechanism of this invention.

Cylindrical casing 11 denes a cup-shaped open end portion 12 at its forward end and a -rearwardly extending reduced portion 13 having a closed end wall 14. A wall 15 separates forward portions 12 from rearward portion 13.

A threaded shaft 16 is journaled axially in walls 14 and 15 by hermetically sealed Teflon bearings 17 and 1S, respectively. Shaft 16 extends forwardly of wall 15 and a squirrel cage impeller indicated generally by 19 is secured to the extended portion of a set screw 20 threaded into a flanged collar 21 xed to an end disc 22. Turbine blades 23 are fixed at their rearward ends to disc 22 and secured by a rim 24 at their forward ends.

As observed in FIG. 2, Pitot tube line '7 opens into portion 12 as at 25.

A detonator block indicated generally by 26 is threadably mounted on shaft 16 by a central threaded bore 27 therein, and houses a detonator element 2S in its upper portion.

Primacord line 8 (see FIG. 4) is adapted to register with detonator 28 when detonator block 26 is in the armed position,

Detonator block 26 is provided with cut out portions 29 and 30 at opposite ends thereof for a purpose to be apparent later.

Detonator 2S is ired by electrical means (not shown) from guidance 4 and contact means are therefore provided for electrical connection of the detonator with the guidance 4. This consists of upper and lower insulated guide rails 31 and 32, respectively, which extend longitudinally in diametrically disposed relation on the inner peripheral surface of the rearward portion 13 of casing 11.

A contact rail 33 which consists of a strip of electro conductive material is carried by the guide rail 31 and a similar contact rail 34 is carried by guide rail 32. However, contact rail 34 terminates at 35, short of rear wall 14, and other length of contact rail 36, spaced from terminal 3S, is carried by the rearward portion of guide rail 32. The space between the rails 34 and 36 is insulated as at 37 from contact rails 34 and 36, best seen in FIG. 2.

Contact rail 33 (see FIG. 3) is connected to contact screw 3S and contact rail 36 is connected to contact screw 39.

Contact rails 33 and 34 are shorted by a shunt wire 46.

Sliding contact is provided between detonator block 26 and the contact rails 33, 34 and 36 and consists of a sliding spring collector 41 in cut out portion 29 of detonator block 26 which wipes on contact rail 33 and another sliding spring collector 42 in cut out portion 30 of detonator block 26 which wipes on contact rails 34 and 36.

A lead 43 connects collector 41 to a firing squib 44 accesos 3 while another lead 45 connects squib 44 to collector 42. Contact screws 38 and 39 are insulated from casing 11 by insulators 54 and 55.

Operation Forward movement in flight of the missile results in entry of dynamic pressure through the Pitot tube line 7 causing rotation of impeller 19 and shaft 16 carried thereby, moving detonator block 26 in the direction of arrow 46 towards arming position at the rear of case 11.

As long as collectors 41 and 42 in detonator block 26 Contact rails 33 and 34, it is impossible for an electric current from guidance 4 to energize squib 44 in the detonator 23 as the circuit is shorted by shunt wire 40.

Upon continued rotation of shaft 16, detonator block 26 proceeds towards the rear of `casing 11 and after collector 42 bridges insulated space 37 it makes sliding contact with short contact rail 36 and the detonator block 26 reaches arming position with Adetonator 28 aligned with primacord S. The circuit is now ready for energizing by guidance 4 as the circuit is completed from guidance 4 through contact screw 9, rail 33, lead 43, squib 44, lead 4S, shunt 4h, rail 34, rail 36, contact screw 39 and lead 10, and the detonator 28 may be fired by mechanism in guidance 4 (not shown).

The powder train from the detonator 28 is through primacord 8 to the warhead 3.

The arming time will depend upon the location of the detonator block 26 in the safe zone consisting of the length of contact rail 34.

Continuous wiping contact of the collectors 41 and 42 insure positive Contact at all times.

The design of the input through Pitot tube line 7 is such that wind velocities such as formed on the surface of the earth will not cause turning-of impeller 19 in event that the cover on the Pitot tube (not shown) is left of outside storage.

The impeller 19 will commence to turn at a time when stagnation pressure becomes sufficient after take off of the missile.

Since the device of the invention utilizes only two moving parts, 26 and 16, its reliability is greatly increased, yet the device more adequately fulfills ordnance safety criteria as the detonator block 26 is prevented from arming by an appreciable displacement thereof as vwell as by misalignment of the detonator block and detonator 28 from the primacord 8, and also by a complete electrical shorting by shunt wire 40 when the detonator block 26 is in the safety zone.

The device of the invention permits of repeated testing of its mechanism while in the field without removing it from the missile.

A system for testing the `device is shown in FIG. 5. The testing system consists of a 4way valve 47, `a compressed air supply 43 which is connected to the arming device 6 by flexible hose 49 and 50. A cam actuator 51 and a timer and motor 52 operates valve 47 and the timer and motor is operated through a resistance bridge 53 and through leads 9 and 10. Pitot tube line 7 and primacord line 8 are disconnected and also the firing voltage from guidance 4 and a reading instrument substituted instead.

A small supply of air from air supply 48 enters hose l 50 and turns impeller 19 and runs the detonator block 26 rearwardly to armed position.

The time of arming would be recorded on the timer 52. Valve 47 is operated by timer 52 also and automatically increases the pressure as a simulated increase in stagnation pressure which occurs in actual missile ight.

A reversal of the pressure connections for instance, when valve 47 is turned to cause air to enter hose 49, carries impeller 19 to return lthe detonator block 26 to its safe position.

Variations and modifications maybe effected without departing from the .scope of the novel concept of the present invention.

What is claimed is:

In a missile including a nose portion, a warhead in said nose portion, a guidance system in said nose portion and a safety and arming mechanism for said missile in said nose portion; said mechanism comprising, a cylindrical casing; an axially disposed, threaded shaft journaled for rotation in said casing; an Vimpeller fixed to the forward end of said shaft; means for rotating said impeller and said shaft by dynamic air pressure comprising a Pitot tube fixed to the forward end of said `nose portion and a hose connecting said Pitot tube and the forward end of said casing `adjacent said impeller; an arming member threadably mounted on said shaft for travel from a safe position within the forward portion of ,said casing towards an armed position at the rearward end of said casing; a detonator housed in said arming member; a firing squib in said detonator; a primacord connected to the rearward portion of said casing and said warhead whereby when said arming member has fully reached said armed position, said detonator will be in alignment with ,said primacord; and electrical conducting means between said squib andsaid guidance system com'- prising, a first contact rail fixed to the inner peripheral surface of said casing and in `electrical connection with said guidance system; a second contact rail fixed to the inner pirepheral surface .of said .casing and in parallel, diametrical relation with respect to said first rail, said second contact rail being of shorter length ,than said first rail, a third contact rail fixed to the inner surface of said casing and in alignment with said second contact rail, said third rail being insulated from said second rail and being electrically connected to said guidance system; a shunt wire shorting said first and second rails; a first spring collector .fixed to the top of said arming member; a second spring collector fixed to the bottom of said arming member, said first collector adapted to wipe said first .rail and said second collector `adapted to wipe said second and third rails respectively, and a lead electrically connecting said first collector, :said squib and said second collector.

ReferencesCited in the le of this `patent UNITED STATES PATENTS 

